A trend in modern medicine is to treat the body without invasive procedures, if possible, because invasive procedures inflict trauma on the patient, and because when the skin is broken the risk of infection to the patient, or others by the patient, increases substantially. When surgery must be performed, it is frequently desirable to use "minimally invasive" procedures as much as possible.
One type of "minimally invasive" procedure is laparoscopic surgery, in which a cannula facilitates using specially-designed surgical instruments to visualize and operate on the interior of the body through a small incision in the patient's body (e.g., through the abdominal wall). In this procedure, a trocar mounted in the cannula helps in introducing the cannula into the peritoneal cavity, which is inflated with carbon dioxide gas to increase the working area available inside the peritoneum. It is desirable to prevent the escape of this gas during the procedure in order to keep the peritoneal cavity inflated sufficiently to maintain room for manipulating surgical instruments. Accordingly, it is desirable to have an air tight seal between the cannula, and the trocar and other surgical instruments used in the cannula.
Separate adapter seals are available from trocar manufacturers that permit the surgeon to use smaller instruments in cannulae designed for larger instruments. Typically, such adapter seals are handed to the surgeon by a nurse, and then snapped into position on the cannula. When the surgeon is done using the small instrument and desires to use a larger instrument, the adapter seal is removed from the cannula and returned to the nurse. Since surgical site and through which surgical instruments are inserted into the cannula.
Generally, an adapter seal of the invention comprises a body portion formed of an elastomeric material, which is adapted for mounting on the proximal end of the cannula. The body portion of the adapter seal has an aperture therein adapted to sealingly engage and support the small instrument while permitting movement of the instrument through the aperture. An insertion guide is mounted on the body portion, and is adapted to guide the small instrument toward the aperture. The insertion guide is relatively rigid in comparison with the body portion. The insertion guide has a wall forming a generally conical passageway for guiding small instruments toward the aperture of the body portion.
Preferably, the adapter seal further includes a tether extending from the body portion of the adapter seal for securely attaching the adapter seal to the cannula. The tether permits the body portion of the adapter seal to be moved between a first position, securely attached to the cannula, yet away from the bore of the cannula, to a second position, wherein the body portion is mounted adjacent the proximal end of the cannula. In the second position, the aperture of the body portion of the adapter seal is substantially aligned with the bore of the cannula, and the proximal end of the bore of the cannula is sealed by the body portion except to flow through the aperture of the body portion. Most preferably, the end of the tether opposite the body portion has a loop thereon adapted to engage the cannula to securely attach the adapter seal to the cannula.
The tether facilitates removing the body portion of the adapter seal from the cannula in order to use a larger surgical instrument while keeping the adapter seal readily available to allow re-connection of the adapter seal to the cannula before a small surgical instrument is used. The tether also reduces the risk of rendering the adapter seal non-sterile when moving it away from the bore of the cannula.
Also, preferably, the adapter seal is adapted for use on a laparoscopic cannula of the type having an annular rim generally adjacent the proximal end of the bore of the cannula. The adapter seal may be so adapted by providing a generally annular rim on the body portion, with a channel formed in the annular rim of the body portion for sealingly engaging the annular rim of the cannula to mount the body portion in its second position on the cannula.
Most preferably, a tab is mounted on the annular rim of the body portion. The tab is adapted to be manually grasped to facilitate removing the body portion from its second position.
The insertion guide is preferably substantially harder than the body portion, and is positioned along the outside surface of the body portion to help protect the body portion from the surgical instruments, which may be very sharp (e.g., a trocar). For example, the loop, tether, body portion, annular rim and tab may be integrally molded of elastomeric material, and the insertion guide may be molded of substantially rigid thermoplastic or thermoset material. Most preferably, the insertion guide provides a lower coefficient of friction than the body portion to help guide the surgical instruments toward the aperture.
In another preferred aspect of the invention, the insertion guide is colored to provide an indication of the size of aperture provided in the body portion. A plurality of adapter seals having different size apertures may be provided for use with one cannula, with each different size aperture being indicated by a different color. Most preferably, the insertion guide is brightly colored for greater visual contrast so as to make it more recognizable even in very low light conditions.
Other features will be pointed out hereinafter.